Struct Sector2

Namespace

Thunder.UnitsNET.Vectors.Geometry

Assembly

Thunder.UnitsNET.Vectors.Geometry.dll

A sector ("pie slice") of a circle in 2D space: the region bounded by two radii and the arc between them.

A sector is defined by:

1. A Circle — provides centre and radius.
2. A StartDirection — the direction from the centre to the start edge.
3. An EndDirection — the direction from the centre to the end edge.
4. A Direction — whether the sweep is clockwise (CW) or counter-clockwise (CCW).

From these, Area, ArcLength, Perimeter, and SweepAngle are computed automatically.

Sector2 is a readonly record struct: value-type, immutable, and equality-by-value.

public readonly record struct Sector2 : IEquatable<Sector2>

Implements

IEquatable<Sector2>

Inherited Members

ValueType.Equals(object)

ValueType.GetHashCode()

ValueType.ToString()

object.Equals(object, object)

object.GetType()

object.ReferenceEquals(object, object)

Extension Methods

CurveDebugDrawExtensions.DebugDraw(Sector2, SpriteBatch, Texture2D, Transform2, Color, float, int)

CurveDebugDrawExtensions.GetDebugScreenVertices(Sector2, Transform2, int)

GeometryXnaExtensions.GetXnaPolyline(Sector2, int?)

GeometryXnaExtensions.GetXnaPolyline(Sector2, LengthUnit, int?)

GeometryXnaExtensions.GetXnaPolyline(Sector2, LengthUnit, Ratio, int?)

Examples

// Quarter-circle sector: unit circle from East to North, CCW
var circle = new Circle2(LengthPoint2.Origin, Radius.FromMeters(1));
var sector = new Sector2(circle, Direction2.East, Direction2.North, ArcDirection.CounterClockwise);

Area area       = sector.Area;       // π/4 ≈ 0.7854 m²
Length arcLen   = sector.ArcLength;  // π/2 ≈ 1.5708 m
Length perim    = sector.Perimeter;  // π/2 + 2 ≈ 3.5708 m

Constructors

Sector2(Circle2, Direction2, Direction2, ArcDirection)

Constructs a Sector2 from a circle, two bounding directions, and a sweep direction.

public Sector2(Circle2 circle, Direction2 startDirection, Direction2 endDirection, ArcDirection direction)

Parameters

circle Circle2

The circle on which the sector lies.

startDirection Direction2

Direction from the centre to the start edge.

endDirection Direction2

Direction from the centre to the end edge.

direction ArcDirection

Sweep direction: CounterClockwise or Clockwise.

Examples

var sector = new Sector2(
    new Circle2(LengthPoint2.Origin, Radius.FromMeters(2)),
    Direction2.East,
    Direction2.North,
    ArcDirection.CounterClockwise);

Properties

ArcLength

The length of the arc forming the curved edge of the sector.

Formula: ArcLength = r · |sweep_radians|

public Length ArcLength { get; }

Property Value

Length

Area

The area of the sector: the "pie slice" region bounded by the two radii and the arc.

Formula: Area = ½ · r² · |sweep_radians|

public Area Area { get; }

Property Value

Area

Center

The centre position of this sector (the centre of its underlying circle).

Alias for Circle.Center. Exposes the position under the standardised Center name shared by all shape types, enabling uniform access and source-generator contracts.

public LengthPoint2 Center { get; }

Property Value

LengthPoint2

Examples

var radius = Radius.FromMeters(2);
var sector = new Sector2(new Circle2(LengthPoint2.FromMeters(3, 4), radius),
                         Direction2.East, Direction2.North, ArcDirection.CounterClockwise);
LengthPoint2 c = sector.Center; // (3, 4) — same as sector.Circle.Center

Circle

The circle on which the sector lies. Provides centre position and radius.

public Circle2 Circle { get; }

Property Value

Circle2

Direction

Whether the sector sweeps clockwise or counter-clockwise from start to end.

public ArcDirection Direction { get; }

Property Value

ArcDirection

EndDirection

The direction from the circle's centre to the second (end) edge of the sector.

public Direction2 EndDirection { get; }

Property Value

Direction2

Perimeter

The total perimeter of the sector: the arc length plus the two straight radii.

Formula: Perimeter = ArcLength + 2 · r

public Length Perimeter { get; }

Property Value

Length

StartDirection

The direction from the circle's centre to the first (start) edge of the sector.

public Direction2 StartDirection { get; }

Property Value

Direction2

SweepAngle

The angle swept from StartDirection to EndDirection in the specified Direction.

Always positive. A full circle has a sweep of 360°.

public Angle SweepAngle { get; }

Property Value

Angle

Methods

Contains(LengthPoint2)

Returns true if point lies inside or on the boundary of this sector.

A point is inside the sector when two conditions are met:

1. Its distance from the circle's centre is ≤ the radius.
2. The direction from the centre to the point falls within the angular span (from StartDirection to EndDirection in the sweep Direction).

public bool Contains(LengthPoint2 point)

Parameters

point LengthPoint2

The point to test.

Returns

bool

true if point is inside or on the sector.

Examples

var circle = new Circle2(LengthPoint2.FromMeters(0, 0), Radius.FromMeters(1));
var sector = new Sector2(circle, Direction2.East, Direction2.North, ArcDirection.CounterClockwise);

sector.Contains(LengthPoint2.FromMeters(0.5, 0.5));  // true  — inside the pie slice
sector.Contains(LengthPoint2.FromMeters(1.0, 1.0));  // false — outside the radius
sector.Contains(LengthPoint2.FromMeters(-0.5, 0));   // false — wrong angular direction

DistanceTo(LengthPoint2)

Returns the distance from this shape to point. Returns UnitsNet.Length.Zero if the point is inside or on the boundary.

public Length DistanceTo(LengthPoint2 point)

Parameters

point LengthPoint2

The point to measure distance to.

Returns

Length

The shortest distance from the shape's boundary to point, or UnitsNet.Length.Zero if the point is contained.

Examples

Length d = shape.DistanceTo(LengthPoint2.FromMeters(10, 0));

GetClosestPoint(LengthPoint2)

Returns the point on the sector's boundary (or interior) nearest to point. If the point is inside the sector it is returned unchanged. Otherwise the minimum-distance candidate among the arc boundary, start edge, and end edge is returned.

public LengthPoint2 GetClosestPoint(LengthPoint2 point)

Parameters

point LengthPoint2

The world-space query point.

Returns

LengthPoint2

The nearest point on or inside the sector.

Examples

var sector = new Sector2(
    new Circle2(LengthPoint2.Origin, Length.FromMeters(2)),
    Direction2.East, Direction2.North, ArcDirection.CounterClockwise);
LengthPoint2 p = sector.GetClosestPoint(LengthPoint2.FromMeters(3, 0)); // (2, 0)

MoveCenterTo(LengthPoint2)

Returns a new Sector2 with its centre moved to newCenter, preserving all other properties.

public Sector2 MoveCenterTo(LengthPoint2 newCenter)

Parameters

newCenter LengthPoint2

The new centre position.

Returns

Sector2

A translated Sector2 centred at newCenter.

Examples

var moved = shape.MoveCenterTo(LengthPoint2.FromMeters(5, 0));

Operators

operator +(Sector2, LengthVector2)

Returns a new Sector2 translated by right. The sweep angles and radius are preserved; only the circle's centre moves.

public static Sector2 operator +(Sector2 left, LengthVector2 right)

Parameters

left Sector2

The sector to translate.

right LengthVector2

The displacement vector.

Returns

Sector2

A new Sector2 with the circle centre shifted by right.